If I go put my hips lower (so lean forward less) I feel noticeably weaker. Should I do so anyway? I keep my torso straight and my eyes in front of me. The best DL I ever did was in terrible form with my back completely arched.

Paul, I personally have never felt a thing in my lats from DLs, but they are involved somewhat in the lift. As long as the bar is very close to your shins, and your back is flat, there is some leeway as to what's the right form. Some of the greatest DLers of all time used almost straightleg form, some pull like they squat. Just don't let your hips rise faster than your shoulders, that's when you get into big trouble. Your individual proportions and body mechanics may recruit the lats in an unfamiliar way.

Paul: The fact that your lats are sore may indicate that you are doing too much "pulling" with your arms from the floor. In the DL, your arms are "merely straps" holding the bar. For me, the DL works my hips, glutes, and quads...thats where I'm most sore.